Melt processable thermoplastic polymer composition

ABSTRACT

A melt processable polymer composition that comprises a thermoplastic non-aliphatic host polymer and a minor but effective amount of a fluoropolymer processing aid, and a method of improving the melt processability of the host polymer are provided.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Ser. No. 60/133,974 filed May13, 1999.

FIELD OF THE INVENTION

This invention relates to a melt processable thermoplastic polymercomposition that employs a non-aliphatic (e.g., a non-hydrocarbon,aromatic, or a non-hydrocarbon/aromatic polymer) non-fluorinated hostpolymer and a fluoropolymer.

BACKGROUND

For any melt processable thermoplastic polymer composition, there existsa critical shear rate above which the surface of the extrudate becomesrough and below which the extrudate will be smooth. See, for example, R.F. Westover, Melt Extrusion, Encyclopedia of Polymer Science andTechnology, Vol. 8, pp 573-81 (John Wiley & Sons 1968). The desire for asmooth extrudate surface competes, and must be optimized with respectto, the economic advantages of extruding a polymer composition at thefastest possible speed (i.e. at high shear rates).

Some of the various types of extrudate roughness and distortion (alsosometimes referred to as melt defects) observed in high and low densitypolyethylenes are described by A. Rudin, et al., Fluorocarbon ElastomerAids Polyolefin Extrusion, Plastics Engineering, March 1986, at 63-66.The authors state that for a given set of processing conditions and diegeometry, a critical shear stress exists above which polyolefins such aslinear low-density polyethylene (LLDPE), high-density polyethylene(HDPE), and polypropylene suffer melt defects. At low shear rates,defects may take the form of “sharkskin”, a loss of surface gloss, thatin more serious manifestations appears as ridges running more or lesstransverse to the extrusion direction. At higher rates, the extrudatecan undergo “continuous melt fracture” becoming grossly distorted. Atrates lower than those at which continuous melt fracture is firstobserved, LLDPE and HDPE can also suffer from “cyclic melt fracture”, inwhich the extrudate surface varies from smooth to rough. The authorsstate further that lowering the shear stress by adjusting theprocessing. conditions or changing the die configuration can avoid thesedefects to a limited extent, but not without creating an entirely newset of problems. For example, extrusion at a higher temperature canresult in weaker bubble walls in tubular film extrusion, and a wider diegap can affect film orientation.

There are other problems often encountered during the extrusion ofthermoplastic polymers. They include a build up of the polymer at theorifice of the die (known as die build up or die drool), excessivebackpressure during extrusion runs, and excessive degradation or lowmelt strength of the polymer due to high extrusion temperatures. Theseproblems slow the extrusion process either because the process must bestopped to clean the equipment or because the process must be run at alower speed.

Certain fluorocarbon processing aids are known to partially improve themelt processability of extrudable thermoplastic hydrocarbon polymers andallow for faster, more efficient extrusion. U.S. Pat. No. 3,125,547 toBlatz, for example, first described the use of fluorocarbon polymerprocess aids with melt-extrudable hydrocarbon polymers wherein thefluorinated polymers are homopolymers and copolymers of fluorinatedolefins having an atomic fluorine to carbon ratio of at least 1:2 andwherein the fluorocarbon polymers have melt flow characteristics similarto that of the hydrocarbon polymers.

U.S. Pat. No. 5,397,829 to Morgan et al. describes the use of copolymersof tetrafluoroethylene and hexafluoropropylene having highhexafluoropropylene content as processing aids in polyolefins.

U.S. Pat. No. 5,464,904 to Chapman et al. discloses the use ofsemicrystalline fluoroplastics such as copolymers of tetrafluoroethyleneand hexafluoropropylene and terpolymers of tetrafluoroethylene,hexafluoropropylene, and vinylidene fluoride with a polyolefin. The onlyenhancement of melt-processability described in this patent is shown inExamples 19 and 25 where a concentration of 1000 ppm of thefluoropolymer in linear low density polyethylene is said to reduce theextrusion pressure of the extrudable composition. There is no showing ofa reduction in melt defects.

U.S. Pat. No. 5,710,217 to Blong at al. discloses an extrudablethermoplastic hydrocarbon composition that comprises an admixture of amelt processable hydrocarbon polymer as the major component and aneffective amount of a chemically-resistant fluoropolymer process aid.The fluoropolymer contains at least 50% by weight of fluorine andcomprises one or more fluoromonomers that are essentially completelyethylenically unsaturated.

U.S. Pat. No. 5,587,429 to Priester discloses a three part processingaid system for polyolefins. The system comprises a fluoropolymer, apolar-side-group-containing adjuvant, and a poly(oxyalkylene) polymer.

U.S. Pat. Nos. 4,904,735 and 5,013,792 (Chapman, Jr. et al.) describe afluorinated processing aid for use with a difficultly melt-processablepolymer comprising (1) a fluorocarbon copolymer which at themelt-processing temperature of the difficultly melt-processable polymeris either in a melted form if crystalline, or is above its glasstransition temperature if amorphous, and (2) at least onetetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene andat least one monomer copolymerizable therewith wherein the mole ratio isat least 1:1, and which is solid at the melt-processable temperature ofthe difficultly melt-processable polymer.

U.S. Pat. Nos. 5,064,594 to Priester et al., and U.S. Pat. No. 5,132,368to Chapman, Jr. et al. describe the use of certain fluoropolymer processaids containing functional polymer chain end groups including —COF,—SO₂F, —SO₂Cl, SO₃M, —OSO₃M, and —COOM, wherein M is hydrogen, a metalcation, or a quaternary ammonium cation for use with a difficultlymelt-processable polymer. These patents each require that thefluoropolymer comprise a molten component and a solid component at theextrusion temperature.

U.S. Pat. Nos. 5,015,693 and 4,855,013 to Duchesne and Johnson disclosethe use of a combination of a poly(oxyalkylene) polymer and afluorocarbon polymer as a processing additive for thermoplastichydrocarbon polymers. The poly(oxyalkylene) polymer and the fluorocarbonpolymer are used at such relative concentrations and proportions as toreduce the occurrence of melt defects during extrusion. Generally theconcentration of the fluoropolymer is present at a level of from 0.005to 0.2 weight percent of the final extrudate and the poly(oxyalkylene)polymer is present at a level of from 0.01 to 0.8 weight percent of thefinal extrudate. Preferably, the weight of the fluorocarbon polymer inthe extrudate and the weight of the poly(oxyalkylene) polymer in theextrudate are in a ratio of 1:1 to 1:10.

EP 0 503 714 Al discloses a polyamide composition comprising

A) 100 parts by weight of a polyamide and

B) 0.001 to 5 parts by weight of a processing agent selected fromfluorinated polymers. These compositions are said to exhibit improvedprocessability as determined by a reduction in the amount of increase inextrusion pressure over time. Polyvinylidene fluoride is the onlyfluoropolymer exemplified in the publication.

While these known additives may provide improved melt processability inolefin polymers, they have not proven to be particularly successful innon-aliphatic polymers. Accordingly, there still exists a need for aneffective processing aid to be used with non-aliphatic polymers.

SUMMARY

It has been discovered that a certain class of fluoropolymers aresurprisingly effective in improving the melt processability ofnon-aliphatic polymers. The improvement in melt processability can beseen in one or more ways. For example, it may be seen in a reduction ofmelt defects such as sharkskin in non-aliphatic polymers, or in thepostponement of the occurrence of these defects to higher extrusionrates than can be typically achieved without the use of thefluoropolymer. Alternatively, it has been discovered that thefluoropolymers are also surprisingly effective in reducing theoccurrence of die build up and/or reducing the amount of backpressureduring extrusion of non-aliphatic polymers, and permitting the use oflower extrusion temperatures to achieve an equivalent throughput.

In one aspect, the present invention provides a novel melt processablepolymer composition that comprises a major amount (i.e., at least (andpreferably greater than) 50% by weight) of a melt processablethermoplastic non-aliphatic host polymer and a minor, but effective,amount of the fluoropolymer processing aid. The fluoropolymer comprisesup to (and preferably less than) 50% by weight of the melt processablepolymer composition. The fluoropolymer may be selected from the groupconsisting essentially of amorphous and partially crystallinefluoropolymers.

In a particularly preferred aspect, the present invention provides anextrudable composition that comprises a fluoropolymer processing aidthat is resistant to reaction with basic, acidic, or amine-containingmoieties in the host polymer or the extrudable composition. These novelcompositions utilize a fluoropolymer processing aid that does notreadily react with or degrade in, the presence of these moieties. Thesefluoropolymer processing aids contain 15% by weight or less ofinterpolymerized units derived from a monomer that produces an acidichydrogen on the backbone of the resulting fluoropolymer afterpolymerization. Preferably, these fluoropolymer processing aids contain10% by weight or less (more preferably 5% by weight or less) ofinterpolymerized units derived from a monomer that produces an acidichydrogen on the backbone of the resulting fluoropolymer afterpolymerization. Most preferably the fluoropolymer processing aids areessentially free of interpolymerized units derived from a monomer thatproduces an acidic hydrogen on the backbone of the resultingfluoropolymer after polymerization.

In yet another aspect, the present invention provides a method forimproving the melt processability of the host polymer. In this methodthe host polymer is mixed with an effective amount of the fluoropolymer.The resulting melt processable polymer composition is preferably mixeduntil there is a uniform distribution of the fluoropolymer in the hostpolymer. The polymer composition is then melt processed.

As used herein, an effective amount of the fluoropolymer is that which(a) reduces the occurrence of melt defects during extrusion of the hostpolymer below the level of melt defects occurring during the extrusionof a host polymer that does not employ the fluoropolymer, or (b) delaysthe onset of the occurrence of such defects to a higher extrusion rate(that is a higher shear rate), or (c) reduces the occurrence of diebuild up, therefore extending the time between cleanup steps, or (d)reduces backpressure, therefore providing faster throughput or allowingthe use of lower extrusion temperatures.

DETAILED DESCRIPTION

The fluoropolymers useful in the invention include both amorphous andpartially crystalline (also referred to herein as semi-crystalline)fluoropolymers. Amorphous fluoropolymers usually do not exhibit a meltpoint. Semi-crystalline fluoropolymers are melt processable per se andhave a melt point.

The selection of an amorphous or semicrystalline fluoropolymer for usein the invention is influenced by a number of factors such as the hostpolymer being used and the processing conditions being employed. In anyevent, the fluoropolymers are incompatible with the host polymer yetpossess a melt viscosity that permits an easy and efficientincorporation into the host polymer melt.

The fluoropolymers useful in the invention are those that are molten atthe temperatures used to extrude (or otherwise melt process) the hostpolymer. They comprise interpolymerized units derived from at least onefluorinated, ethylenically unsaturated monomer, preferably two or moremonomers, of the formula

RCF═C(R)₂  (II)

wherein R is selected from H, F, Cl, alkyl of from 1 to 8 carbon atoms,aryl of from 1 to 8 carbon atoms, cyclic alkyl of from 1 to 10 carbonatoms, or perfluoroalkyl of from 1 to 8 carbon atoms or a functionalgroup that may contain 1 or more hetero atoms. The R group preferablycontains from 1 to 3 carbon atoms. In this monomer each R group may bethe same as each of the other R groups. Alternatively, each R group maybe different from one or more of the other R groups.

The fluoropolymers may also comprise a copolymer derived from theinterpolymerization of at least one formula I monomer with at least onenonfluorinated, copolymerizable comonomer having the formula

(R¹)₂C═C(R¹)₂  (II)

wherein each R¹ is independently selected from H, Cl, or an alkyl groupof from 1 to 8 carbon atoms, a cyclic alkyl group of from 1 to 10 carbonatoms, or an aryl group of from 1 to 8 carbon atoms. R¹ preferablycontains from 1 to 3 carbon atoms.

Representative examples of useful fluorinated formula I monomersinclude, but are not limited to, vinylidene fluoride,tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene,2-chloropentafluoropropene, dichlorodifluoroethylene,1,1-dichlorofluoroethylene, and mixtures thereof. Perfluoro-1,3-dioxolesmay also be used. The perfluoro-1,3-dioxole monomers and theircopolymers are described in U.S. Pat. No. 4,558,141 (Squires).

Representative examples of useful formula II monomers include ethylene,propylene, etc.

Especially useful fluoropolymers include those derived from theinterpolymerization of two or more different formula I monomers andoptionally one or more formula I monomers with one or more formula IImonomers. Examples of such polymers are those derived frominterpolymerized units derived from vinylidene fluoride (VDF) andhexafluoropropylene (HFP); and those derived from tetrafluoroethylene(TFE) and at least 5 weight % of at least one copolymerizable comonomerother than TFE. This latter class of fluoropolymers includes polymers ofinterpolymerized units derived from TFE and HFP; polymers ofinterpolymerized units derived from TFE, HFP, and VDF; polymers ofinterpolymerized units derived from TFE, HFP and a formula II monomer;and polymers derived from interpolymerized units derived from TFE and aformula II monomer.

A preferred subclass of fluoropolymers useful in the invention are thesemicrystalline fluoropolymers, also referred to herein asfluoroplastics. These polymers generally have a peak melting temperatureof from 60° to 300° C. The fluoroplastics may be homopolymers orcopolymers of a monomer of formula I or copolymers of at least onemonomer of formula I with at least one monomer of formula II. Examplesof preferred subclasses of fluorothermoplastic polymers useful in theinvention include the following:

A. Fluorothermoplastics derived solely from VDF and HFP. Preferably,these fluorothermoplastics have interpolymerized units derived from 99to 67 weight percent of VDF and from 1 to 33 weight percent HFP, morepreferably from 90 to 67 weight percent VDF and from 10 to 33 weightpercent HFP.

B. Fluorothermoplastics having interpolymerized units derived solelyfrom (i) TFE, (ii) more than 25 weight percent of one, preferably two,ethylenically unsaturated copolymerizable fluorinated monomers otherthan TFE having the general structure of formula I. A preferred class ofthese fluoroplastics is derived from copolymerizing 30 to 70 weight %TFE, 10 to 30 weight %, HFP, and 5 to 50 weight %, preferably 10 to 45weight % of a third comonomer other than TFE and HFP having the generalstructure of formula I. A subclass of this preferred class offluoropolymer is derived from copolymerization of a monomer charge ofTFE (preferably in an amount of 45 to 65 weight %), HFP (preferably inan amount of 10 to 30 weight %), and VDF (preferably in an amount of 15to 35 weight %). A subspecies of these fluoroplastics useful as thefluoropolymer comprises the multimodal fluoroplastics described inapplication Ser. No. 09/311,111, filed of even date herewith, now U.S.Pat. No. 6,242,548, incorporated herein by reference.

C. Fluorothermoplastics derived from copolymerization of a monomercharge of TFE (preferably from 45 to 70 weight %), HFP (preferably from10 to 20 weight %) and a formula II monomer, preferably an alpha olefinhydrocarbon ethylenically unsaturated comonomer having from 1 to 3carbon atoms, such as ethylene or propylene (preferably from 10 to 20weight %).

D. Fluorothermoplastics derived from TFE and a monomer having thegeneral structure of formula II. Particularly preferred polymers of thissubclass are copolymers of TFE and propylene. Such copolymers arepreferably derived by copolymerizing from 80 to 95 weight %, morepreferably from 85 to 90 weight %, of TFE with from 20 to 5 weight %,more from preferably from 15 to 10 weight %, of the Formula IIcomonomer.

Another preferred subclass of fluoropolymers useful in the invention arethe amorphous fluoropolymers. Examples of preferred amorphousfluoropolymers include the following:

A. Amorphous polymers derived from TFE and propylene. These polymerstypically have interpolymerized units derived from 50-80 weight percentTFE and from 50 to 20 weight percent propylene.

B. Amorphous polymers derived from TFE, VDF, and propylene. Thesepolymers typically have interpolymerized units derived from 45 to 80weight percent TFE, from 5 to 40 weight percent VDF and from 10 to 25weight percent propylene.

C. Amorphous polymers derived from VDF and HFP. These polymers typicallyhave interpolymerized units derived from 30 to 90 weight percent VDF andfrom 70 to 10 weight percent HFP.

As discussed previously, when either the host polymer or the extrudablecomposition contains reactive functionality (e.g., a basic, acidic or anamine-containing functionality), the fluoropolymer preferably contains15% by weight or less of interpolymerized units derived from a monomerthat produces an acidic hydrogen on the backbone of the resultingfluoropolymer after polymerization. This preserves the stability of thefluoropolymer in the extrudable composition. Thus, it is preferable thatthe use of such monomers that yield an acidic hydrogen be minimized.Accordingly, the fluoropolymer preferably contains less than 10% byweight of such units, more preferably less than 5% by weight of suchunits, and most preferably is essentially free of such units. Generally,monomers in which one vinyl carbon atom is perfluorinated (i.e. issaturated with fluorine atoms) and in which the other vinyl carbon atomcontains at least one hydrogen atom will yield acidic hydrogen atoms onthe backbone of a fluoropolymer into which they are polymerized, leavingthe fluoropolymer susceptible to chemical attack by a base. This monomerclass includes vinylidene fluoride, trifluoroethylene,1-hydropentafluoropropene, and 2-hydropentafluoropropene.

Examples of useful commercially available amorphous and semicrystallinefluoropolymers include DYNAMAR™ FX 9613, DYNEON™ THV 200 and DYNEON™ THV400 all available from Dyneon LLC, Oakdale, Minn. Other usefulcommercially available materials include the KYNAR™ fluoropolymersavailable from Solvay and the AFLAS™ fluoropolymers available from AsahiGlass.

The amount of the fluoropolymer used as the process additive istypically relatively low. The exact amount used,may be varied dependingupon whether the melt-processable composition is to be extruded into itsfinal form (e.g., as a tube or film) or whether it is to be used as amasterbatch which is to be further diluted with additional host polymerbefore being extruded into its final form. Generally, the fluoropolymercomprises from about 0.005 to 50 weight percent of the melt processablepolymer composition. If the melt processable polymer composition is amasterbatch, the amount of the fluoropolymer may vary between about 2 to50 weight percent of the composition. If the melt processable polymercomposition is to be extruded into final form and is not further dilutedby the addition of host polymer, it typically contains a lowerconcentration of the fluoropolymer, e.g., about 0.005 to 2 weightpercent, and preferably about 0.01 and 0.2 weight percent of themelt-processable composition. In any event, the upper concentration ofthe fluoropolymer used is generally determined by economic limitationsrather than by any adverse physical effect of the concentration of theprocessing aid.

The host polymers useful in the invention are non-aliphatic,non-fluorinated polymers. The non-aliphatic host polymers useful in theinvention include, by way of example, non-hydrocarbon polymers, aromaticpolymers, non-hydrocarbon/aromatic polymers, etc. Non-hydrocarbonpolymers are those that, in addition to carbon and hydrogen, containother atoms such as a heteroatom (e.g., oxygen, nitrogen, sulfur,phosphorus) in the backbone or in a pendant group. The aromatic hostpolymers useful in the invention are those that contain at least onearomatic group in the backbone or in a pendant group.Non-hydrocarbon/aromatic polymers useful in the invention are those thatcontain atoms other than carbon and hydrogen plus aromatic groups intheir backbone or in a pendant group. The host polymer may sometimesalso be referred to as a polar polymer. By this is meant that thepolymer contains polar substituents. The term “non-fluorinated polymer”as used herein means that less than 3% of the C—H bonds of the hostpolymer can be C—F bonds.

A wide variety of non-aliphatic polymers are useful as the host polymerin the present invention. They include, but are not limited to,polyamides, polyimides, polyurethanes, polyesters, polycarbonates,polyketones, polyureas, polyacrylates, polymethylacrylates, polystyrenes(especially homopolymers of styrene) and polyvinyls (especiallyhomopolymers of a vinyl chloride monomer).

Useful host polymers also include blends of various thermoplasticpolymers and blends thereof containing conventional adjuvants such asantioxidants, light stabilizers, fillers, antiblocking agents, andpigments. The host polymers may be used in the form of powders, pellets,granules, or in any other extrudable form.

Polyamides and polyimides represent two classes of polymer that containa reactive functionality. When these polymers are used as a hostpolymer, the fluoropolymer most preferably is one that contains lessthan 15% by weight of interpolymerized units derived from monomers thatproduce an acidic hydrogen on the fluoropolymer.

The melt processable composition of the invention can be prepared by anyof a variety of ways. For example, the host polymer and thefluoropolymer processing additive can be combined together by any of theblending means usually employed in the plastics industry, such as with acompounding mill, a Banbury mixer, or a mixing extruder in which theprocessing additive is uniformly distributed throughout the hostpolymer. The processing additive and the host polymer may be used in theform, for example, of a powder, a pellet, or a granular product. Themixing operation is most conveniently carried out at a temperature abovethe melting point or softening point of the fluoropolymer, though it isalso feasible to dry-blend the components in the solid state asparticulates and then cause uniform distribution of the components byfeeding the dry blend to a twin-screw melt extruder.

The resulting melt-blended mixture can be pelletized or otherwisecomminuted into a desired particulate size or size distribution and fedto an extruder, which typically will be a single-screw extruder, thatmelt-processes the blended mixture. Melt-processing typically isperformed at a temperature from 180° to 320° C., although optimumoperating temperatures are selected depending upon the melting point,melt viscosity, and thermal stability of the blend. Different types ofextruders that may be used to extrude the compositions of this inventionare described, for example, by Rauwendaal, C., “Polymer Extrusion,”Hansen Publishers, p. 23-48, 1986. The die design of an extruder canvary, depending on the desired extrudate to be fabricated. For example,an annular die can be used to extrude tubing, useful in making fuel linehose, such as that described in U.S. Pat. No. 5,284,184 (Noone et al.),which description is incorporated herein by reference.

The blended composition can contain conventional adjuvants such asantioxidants, antiblocks, pigments, and fillers, e.g. titanium dioxide,carbon black, and silica. Antiblocks, when used, may be coated oruncoated materials. When these adjuvants contain reactivefunctionalities such as have been discussed above, it is highlypreferred that the fluoropolymer contain less than 15% by weight ofinterpolymerized units derived from a monomer that produces an acidichydrogen on the backbone of the resulting polymer.

The fluoropolymer processing additive may also be combined with apoly(oxyalkylene) polymer component. The poly(oxyalkylene) polymercomponent may comprise one or more poly(oxyalkylene) polymers. A usefulprocessing additive composition comprises between about 5 and 95 weightpercent of the poly(oxyalkylene) polymer component and 95 and 5 weightpercent of the fluoropolymer. Typically, the ratio of the fluoropolymerto the poly(oxyalkylene) polymer component in the processing aid will befrom 1/2 to 2/1.

The poly(oxyalkylene) polymer component generally may comprise betweenabout 0.005 and 20 weight percent of the overall melt processablecomposition, more preferably between about 0.01 and 5 weight percent,and most preferably between about 0.02 and 1 weight percent.

Generally, poly(oxyalkylene) polymers useful in this invention includepoly(oxyalkylene) polyols and their derivatives. A class of suchpoly(oxyalkylene) polymers may be represented by the general formula:

A[(OR³)_(x)OR²]_(y)

wherein:

A is an active hydrogen-free residue of a low molecular weight,initiator organic compound having a plurality of active hydrogen atoms(e.g., 2 or 3), such as a polyhydroxyalkane or a polyether polyol, e.g.,ethylene glycol, glycerol, 1,1,1-trimethylol propane, andpoly(oxypropylene) glycol;

y is 2 or 3;

(OR³)_(x) is a poly(oxyalkylene) chain having a plurality of oxyalkylenegroups, (OR³), wherein the R³ moieties can be the same or different andare selected from the group consisting of C₁ to C₅ alkylene radicalsand, preferably, C₂ or C₃ alkylene radicals, and x is the number ofoxyalkylene units in said chain. Said poly(oxyalkylene) chain can be ahomopolymer chain, e.g., poly(oxyethylene) or poly(oxypropylene), or canbe a chain of randomly distributed (i.e., a heteric mixture) oxyalkylenegroups, e.g., a copolymer —OC₂H₄— and —OC₃H₆— units, or can be a chainhaving alternating blocks or backbone segments of repeating oxyalkylenegroups, e.g., a polymer comprising OC₂H₄_(a) and OC₃H₆_(b) blocks,wherein a+b=5 to 5000 or higher, and preferably 10 to 500.

R² is H or an organic radical, such as alkyl, aryl, or a combinationthereof such as aralkyl or alkaryl, and may contain oxygen or nitrogenheteroatoms. For example, R² can be methyl, butyl, phenyl, benzyl, andacyl groups such as acetyl (CH₃CO—), benzoyl (C₆H₅CO—) and stearyl(C₁₇H₃₅CO—).

Representative poly(oxyalkylene) polymer derivatives can includepoly(oxyalkylene) polyol derivatives wherein the terminal hydroxy groupshave been partly or fully converted to ether derivatives, e.g., methoxygroups, or ester derivatives, e.g., stearate groups, (C₁₇H₃₅COO—). Otheruseful poly(oxyalkylene) derivatives are polyesters, e.g., prepared fromdicarboxylic acids and poly(oxyalkylene) glycols. Preferably, the majorproportion of the poly(oxyalkylene) polymer derivative by weight will bethe repeating oxyalkylene groups, (OR¹).

The poly(oxyalkylene) polyols and their derivatives can be those whichare solid at room temperature and have a molecular weight of at leastabout 200 and preferably a molecular weight of about 400 to 20,000 orhigher. Poly(oxyalkylene) polyols useful in this invention includepolyethylene glycols which can be represented by the formulaH(OC₂H₄)_(n)OH, where n is about 15 to 3000, such as those sold underthe Carbowax trademark, such as Carbowax™ PEG 8000, where n is about181, and those sold under the trade name Polyox, such as Polyox™ WSRN-10 where n is about 2272.

The following examples further illustrate the present invention. Unlessotherwise indicated, in all of the examples, the samples were extrudedin a Haake Polylab system and a TW-100 counter-rotating, intermeshing,conical twin-screw extruder (Haake). The extruder was used to prepareconcentrates containing 3 weight % fluoropolymer processing additive(PPA). For the viscosity measurements, the PPA was added by dilution ofthe concentrate to obtain a final concentration of 1000 parts permillion (ppm) of the PPA.

Before introduction of each PPA-polymer combination, the extruder anddie were thoroughly cleaned. This was achieved by first purging withpolyethylene, followed by a 70% CaCO₃ polyethylene masterbatch (HM-10,Heritage Plastics), polyethylene again, and finally clean polymer(polystyrene, nylon or polyester). The extruder was cooled to 190° C.before introducing the CaCO₃ masterbatch to prevent scorching of themasterbatch.

The viscosity of the resins was measured by using the same extruderwhich was equipped with a capillary die. The die had a diameter of 1.2mm and a 40 length/diameter (L/D) ratio. The temperature profile wasselected to obtain even extrusion conditions and control the melttemperature. In each case, the extrusion rate and the pressure wasrecorded for a range of outputs. The viscosity and shear stress wereplotted against the shear rate and in the cases where melt fractureoccurred, the lowest shear rate where melt was visible (melt fractureonset) was recorded. Tables 1 and 2 list the additives and resins used.

In these Tables, the following abbreviations have the following meaning:

E = ethylene HFP = hexafluoropropylene P = propylene TFE =tetrafluoroethylene VDF = vinylidene fluoride MFI = Melt Flow Indexmeasured in accordance with ASTM D- 1238 at a support weight of 5 kg anda temperature of 265° C. (2.1 mm diameter extrusion die/8 mm length)

TABLE 1 PPA PPA Monomer Tm Sample # Additive Type Weight % (° C.)Viscosity PPA-1 Copolymer 60/40 — Mooney = 32 VDF/HFP PPA-2 Terpolymer42/38/20 120 MFI 5/265 = 20 VDF/HFP/TFE PPA-3 Copolymer 85/15 100 MFI5/265 = 14 TFE/P PPA-4 Terpolymer 63/20/17 205 MFI 5/265 = 10 HFP/TFE/EPPA-5 Copolymer 85/15 100 MFI 5/265 = 12 TFE/P PPA-6 Terpolymer 57/30/13165 MFI 5/265 = 10 HFP/TFE/E PPA-7 Terpolymer 60/22/18 160 MFI 5/265 =60 VDF/HFP/TFE PPA-8 Terpolymer 60/22/18 160 MFI 5/265 = 250 VDF/HFP/TFEPPA-9 Terpolymer 42/38/20 120 MFI 5/265 = 14 VDF/HFP/TFE

TABLE 2 Host Polymer Sample # Polymer Type Polymer Name SupplierViscosity Resin A Syndiotactic Questra MA406 Dow MFI = 3.5 polystyreneChemical Company Resin B Polyamide 6,6 Zytel 101 Dupont Resin CPolyamide 6,6 Celanese 1100 Celanese Fiber Resin (natural) Resin DPolyethylene Eastapak 9663 Eastman Fiber Resin Terephthalate IV = 0.74Resin E Polyvinyl Fully formulated Vintex Chloride

EXAMPLE 1

A sample of Resin A, a syndiotactic polystyrene (Questra MA406 from theDow Chemical Company), was extruded with a target melt temperature of300° C.

Table 3 below gives the viscosity as measured for the resin with andwithout additive. The additive was added at a level of 1000 ppm: In eachcase, the first shear rate where melt fracture was observed (onset ofmelt fracture) is indicated. The resin without additive has an onset ofapproximately 100/s whereas all the additives provide an onset greaterthan 1000/s.

Table 4 summarizes the performance of the PPA. The addition of PPA toResin A delays the onset of melt fracture to higher shear rate andprovide some pressure reduction.

TABLE 3 Viscosity of Syndiotactic Polystyrene with PPA Base Line Resin AResin A + PPA 1 Resin A + PPA 2 Resin A + PPA 3 Apparent ApparentApparent Apparent Shear Rate Viscosity Shear Rate Viscosity Shear RateViscosity Shear Rate Viscosity [s⁻¹] [Pa · s] [s⁻¹] (Pa · s) [s⁻¹] (Pa ·s) [s⁻¹] [Pa · s] 25 343.4 87 285.0 120 320.4 1293 84.5 109* 298.1 442163.4 393 182.5 1555 75.1 723 130.6 799 116.8 1140 94.6 1823 66.3 873123.7 1236* 87.3 1402* 85.0 1855 66.5 1542 78.0 1757 67.2 1675 72.22210* 57.4 1937 64.0 1918 63.3 1994 64.2 2442 53.8 2297 56.4 2431 52.22769 48.7 2958 46.3 2982 44.6 3124 45.0 3430 41.4 3664 38.2 4169 36.55451 29.6 4024 34.6 4294 34.9 *Onset of melt fracture.

TABLE 4 Performance of PPA in Polystyrene Pressure Reduction Onset of MFat 1300/s* Sample (1/s) (%) No PPA 109 N/A PPA-1 1236 10 PPA-2 1402 6PPA-3 2210 11 *Interpolated values

EXAMPLE 2

A sample of Resin C, a Polyamide 6,6 (Celanese 1100), was extruded witha target melt temperature of 300° C. The additive was added through aconcentrate to obtain a final concentration of 1000 ppm. For nylonextrusion a purge compound containing silica (Polybatch KC-15, A.Schulman) was used in place of the CaCO₃ masterbatch. Two experimentswere repeated in which the extruder was purged with the CaCO₃masterbatch in one case and with the silica masterbatch in the secondcase.

Table 5 below gives the shear stress vs. shear rate for the base resinand the resin containing a PPA. A repeat sample was tested for thePPA-5. In each case, a lower shear stress is observed with PPA. Theshear stress was interpolated at a fixed shear rate of 600/s forcomparison purposes. This is given in Table 6 along with the calculatedpressure reduction obtained from the PPA. From Table 5, the benefitprovided by the PPA is clearly shown. Here a multimodal sample (PPA-5)gives better performance than a unimodal sample (PPA-3).

TABLE 5 Shear Stress of Polyamide with PPA Baseline Resin C + BaselineResin C + Resin C + Resin C + Resin C PPA-5 Resin C PPA-3 PPA-5 PPA-6(Repeat) (Repeat) Shear Shear Shear Shear Shear Shear Shear Shear ShearShear Shear Shear Rate Stress Rate Stress Rate Stress Rate Stress RateStress Rate Stress [s⁻¹] [kPa] [s⁻¹] [kPa] [s⁻¹] [kPa] [s⁻¹] [kPa] [s⁻¹][kPa] [s⁻¹] [kPa] 76 9.7 109 9.6 87 8.6 131 6.0 240 33.4 221 26.3 24328.8 292 17.4 353 47.9 343 31.0 336 42.9 347 37.4 300 31.7 439 25.7 54264.3 666 63.3 417 51.9 393 45.9 390 40.3 469 27.0 711 83.3 899 89.2 55166.9 540 63.7 472 51.9 562 38.4 1127 119.0 960 92.8 682 82.9 666 78.2557 63.9 696 46.7 1573 155.6 1273 87.8 715 96.7 761 89.8 734 76.0 87355.9 1370 126.5 939 110.3 865 103.0 857 86.6 944 64.3 955 119.7 1031117.7 936 97.3 952 77.4 1094 136.1 1070 125.6 1102 111.4 1020 86.1

TABLE 6 Performance of PPA in Polyamide Shear Stress @ Pressure 600/sreduction (kPa) (%) Resin C 72.8 Resin C + PPA 3 70.6 3 Resin C + PPA 566.8 8 Resin C + PPA 6 40.7 44 Resin C — Repeat 70.8 Resin C + PPA 5Repeat 56.7 20

EXAMPLE 3

In order to simulate the high shear and temperatures obtained incompounding, a batch mixer was used. A 5 weight % concentrate of PPA inResin B was compounded at 300° C. for 10 min, in a Haake Rheocord 90using a Rheomix™ 3000 bowl fitted with roller blades. In this case, avisual analysis of the color of the samples was done. One can see fromTable 7 that the PPA containing VDF can react with polyamide anddiscolor the sample. This shows the benefit of using non-reactive (nonVDF) PPA.

It was unexpected that VDF containing polymer would react with nylon toproduce a discolored material.

TABLE 7 Sample Discoloration PPA Concentration in Sample Color Resin BPPA 1 Dark brown 5 weight % PPA 4 Beige 5 weight %

EXAMPLE 4

A sample of Resin D, a Polyethylene terephtalate (Eastapak 9663 fromEastman), was extruded with a target melt temperature of 305° C.

Table 8 shows the shear stress vs. shear rate for the resin and theresin with additives. One can clearly see the reduction in stress athigher shear rates. Here lower Mw (higher MFI) provides betterperformance. This indicates that the PPA is preferably selected to matchthe resin in which it is used. Table 9 summarizes the pressure reductionobtained for Resin D.

TABLE 8 Shear Stress of PET with PPA Resin PPA-6 PPA-7 PPA-8 Shear ShearShear Shear Shear Shear Shear Shear Rate Stress Rate Stress Rate StressRate Stress (s⁻¹) (kPa) (s⁻¹) (kPa) (s⁻¹) (kPa) (s⁻¹) (kPa) 124 9.4 54649.9 220 13.4 535 36.4 226 14.3 831 75.9 529 44.2 1001 75.2 480 33.71329 119.4 1050 91.1 1142 77.7 1568 133.8 1364 125.7 1173 93.8 1161 75.91656 157 1836 130.5 1483 106.3 1470 80.6 1847 169.5 1967 137.1 1901 1271580 81.7

TABLE 9 Pressure Reduction in PET Pressure Reduction at 1500/s* Sample(%) PPA-6 0 PPA-7 16 PPA-8 37 *Interpolated values

EXAMPLE 5

A sample of Resin E, a polyvinyl chloride, was extruded with a targetmelt temperature of 160° C. and a shear rate of 580/s. Under thoseconditions, a pressure reduction of 12% was observed with the additionof 1000 ppm of PPA-9 as compared to the resin without PPA.

In this case, the time required to observe die build-up was alsorecorded. The resin without PPA led to die build-up in approximately 3minutes, whereas the resin with PPA-9 was still build-up free after 30minutes.

What is claimed is:
 1. A melt processable polymer composition comprisinga major amount of a melt processable thermoplastic non-fluorinated hostpolymer selected from a polyamide, a polyimide, a polyurethane,polyethylene terephthalate, a polycarbonate, a polyketone, a ployurea,polystyrene, and polyvinyl chloride, and blends thereof and a minoramount of a solid fluoropolymer processing additive; wherein theadditive comprises interpolymerized units derived from one or morenon-fluorinated monomer(s) having the formula (R¹)₂C═C(R¹)₂  whereineach R¹ may be the same or different and is selected from H, Cl, or analkyl group of from 1 to 8 carbon atoms, a cyclic alkyl group of from 3to 10 carbon atoms, or aryl group of from 6 to 8 carbon atoms; andwherein the fluoropolymer contains 15% by weight or less ofinterpolymerized units derived from a monomer that produces an acidichydrogen on the backbone or the resulting polymer after polymerizationwith the proviso that when the host polymer is a polyamide, thefluoropolymer processing additive is a terpolymer.
 2. A melt processablecomposition according to claim 1 wherein the host polymer comprises fromabout 50 to 99.995 weight % of the composition.
 3. A melt processablecomposition according to claim 1 wherein the fluoropolymer processingadditive is amorphous.
 4. A melt processable composition according toclaim 1 wherein the fluoropolymer processing additive is partiallycrystalline.
 5. A melt processable composition according to claim 4wherein the fluoropolymer processing additive is multimodal.
 6. A meltprocessable composition according to claim 1 wherein the fluoropolymercomprises interpolymerized units derived from monomers selected fromtetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, andperfluoroalkyl vinyl ethers.
 7. A processing additive compositionaccording to claim 1 wherein the fluoropolymer comprisesinterpolymerized units derived from tetrafluoroethylene,hexafluoropropylene, and ethylene.
 8. A melt processable polymercomposition according to claim 1 wherein the host polymer contains areactive functionality thereon.
 9. A melt processable compositionaccording to claim 1 wherein the monomer that produces acidic hydrogenis selected from the group consisting of vinylidene fluoride,trifluoroethylene, 1-hydrofluoropropene and 2-hydropentafluoropropene.10. An extrudable composition according to claim 1 wherein thefluoropolymer processing aid further comprises a poly(oxyalkylene)polymer.
 11. An extruded article according to claim 10 wherein thearticle comprises a film, tube, or container.
 12. An extruded articlecomprising the composition of claim
 1. 13. A melt processablecomposition according to claim 1 wherein the interpolymerized units ofone or more non-fluorinated monomer(s) are selected from ethylene and/orpropylene.
 14. A melt processable composition according to claim 1wherein the fluoropolymer additive comprises interpolymerized unitsderived from tetrafluoroethylene and/or hexafluoropropylene.
 15. A meltprocessable composition according to claim 14 wherein the fluoropolymeradditive comprises interpolymerized units derived from vinylidenefluoride.
 16. The melt processable composition of claim 1 wherein thefluoropolymer additive comprises interpolymerized units derived from twofluorinated monomers along with the one non-fluorinated monomer(s). 17.A method for improving the melt processability of a melt processablethermoplastic host polymer selected from a polyamide, a polyimide, apolyurethane, polyethylene terephthalate, a polycarbonate, a polyketone,a polyurea, polystyrene, and polyvinyl chloride, and blends thereofwhich comprises the steps of: forming a melt processable polymercomposition comprising a major amount of the host polymer and aneffective amount but minor amount of a dry fluoropolymer processingadditive, wherein the additive comprises interpolymerized units derivedfrom one or more non-fluorinated monomers(s) having the formula(R¹)₂C═C(R¹)₂ wherein each R¹ may be the same or different and isselected from H, Cl, or an alkyl group of from 1 to 8 carbon atoms, acyclic alkyl group of from 3 to 10 carbon atoms, or aryl group or from 6to 8 carbon atoms; wherein the fluoropolymer contains 15% by weight orless of interpolymerized units derived form a monomer that produces anacidic hydrogen on the backbone of the resulting polymer afterpolymerization with the proviso that when the host polymer is apolyamide, the fluoropolymer processing additive is a terpolymer; andwherein the fluoropolymer optionally is multimodal; melt-mixing or dryblending the processing additive and the host polymer for a timesufficient to blend them together; and melt processing the polymercomposition.
 18. A method according to claim 17 wherein the meltprocessable polymer composition comprises from 50 to 99.995 weightpercent of the host polymer and from 50 to 0.005 weight percent of thefluoropolymer processing additive.
 19. A method according to claim 17wherein the improvement in melt processability comprises a reduction inmelt defects in the melt processed host polymer.
 20. A method accordingto claim 17 wherein the improvement in melt processability comprises areduction in die build-up during melt processing of the host polymer.21. A method according to claim 17 wherein the improvement in meltprocessability comprises a reduction in back pressure during meltprocessing of the host polymer.
 22. A melt processable polymercomposition comprising a major amount of a melt processablethermoplastic non-fluorinated host polymer selected from non-hydrocarbonpolymers, aromatic polymers, and non-hydrocarbon/aromatic polymers and aminor amount of a multimodal partially crystalline fluoropolymerprocessing additive.